The present invention relates to a coil unit utilized for non-contact power transmission using a coil, an electronic instrument, and the like.
Non-contact power transmission that utilizes electromagnetic induction to enable power transmission without metal-to-metal contact has been known. As application examples of non-contact power transmission, charging a portable telephone, charging a household appliance (e.g., telephone handset), and the like have been proposed.
Non-contact power transmission has a problem in that a transmission coil generates heat. Technologies for suppressing such heat generation have been proposed. JP-A-8-103028 discloses a design method that suppresses heat generation during non-contact charging. JP-A-8-148360 discloses technology that suppresses heat generation by adapting a suitable configuration of a coil and a magnetic material. JP-A-11-98705 discloses a non-contact charging device provided with an air-cooling mechanism. JP-A-2003-272938 discloses a structure in which a ceramic is disposed between a primary coil and a secondary coil to dissipate heat. JP-A-2005-110357 discloses the structure of a housing with an improved heat dissipation capability.